The Preparation And Hydrogenation Performance Study Of Ruthenium Based Mesoporous Carbon Catalysts

Carbon supported ruthenium catalysts are widely used in the field of chemical industry for they have excellent catalytic performance in hydrogenation reaction of nitrogen, carbon monoxide, benzene and fine chemicals etc. The present paper studied on the pore structure and graphitic degree of mesoporous carbons, to investigate their influence on the Ru-based catalysts for hydrogenation. Moreover, we prepared semi-embedded Ru-based catalysts by an in-situ carbonization method with a series of studies and optimization. Comparison of semi-embedded and supported Ru-based catalysts was studied. The main results are as follows:1. The effect of templates(SBA-15 and nano-sized SiO2), particle sizes and addition ammonts of SiO2 on the pore structure of MCs and catalytic performance of their supported Ba-Ru-K/MC catalyst in ammonia synthesis was studied. MC prepared with SiO2 has a larger pore structure and thinner carbon wall than OMC prepared with SBA-15. The catalytic performance of Ba-Ru-K/MC catalyst is better than that of Ba-Ru-K/OMC. The surface areas of MCs increase linearly with the ammonts of SiO2. And the catalytic performance for ammonia synthesis increases linear with the mesoporous surface areas of MCs.2. The influence of graphitization catalyst, carbonization temperature, heating rate and carbon source on the graphitic degree of MC and catalytic performance of their supported Ba-Ru-K/MC catalysts was studied. The graphitic degree of MCs increases with the increase of calcined temperatures. Ba-Ru-K/GC-900 supported on GC-900 which is prepared with Ni and calcined under 900 oC has a better excellent catalytic performance and resisitance of methanation for ammonia synthesis.3. Semi-embedded ruthenium catalyst(Ru-MC) prepared via an in-situ carbonization method has the strengths of pore structure, high dispersion of Ru nanoparticles and strong interaction between carbon and Ru nanoparticles. The catalytic performance of Ru-MC over toluene hydrogenation is 20 times higher than MC supported catalyst(Ru/MC). The TOF value of Ru-MC is 16 s-1under reaction conditions of 4 MPa and 100 oC. Ru-MC with dual promotors of Ba and K(Ba-K/Ru-MC) has an excellent catalytic performance and stability over ammonia synthesis. The intrinsic activity of Ba-K/Ru-MC is 2 times higher than supported catalyst(Ba-Ru-K/MC) and 6 times higher than industrial fused-iron catalyst. The reaction rate of Ba-K/Ru-MC is 133 mmol/(gcatal.h) at 425 oC, 10 MPa and a gas hourly space velocity of 10000 h-1.4. Semi-embedded catalysts prepared via one-pot solid gringding method were studied and good results were obtained. Ru@C/SiO2 was prepared via a carbon coated method. When C/Ru=2, Ru particle size is the smallest, and the catalytic performance over hydrogenation acheieves the highest, which is 3 times higher than Ru/SiO2.